Supplementary Balance Sheet Information (Tables)

12 Months Ended

Dec. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Inventories

Inventories

	December 31,
	2018		2017
Raw materials	$	69,008	$	57,277
Work-in-process		15,982		14,847
Finished goods		17,337		16,443
Demo and consigned inventory		2,437		2,711
Total inventories	$	104,764	$	91,278

Property, Plant and Equipment, net

Property, Plant and Equipment, Net

	December 31,
	2018			2017
Cost:
Land, buildings and improvements	$	56,068		$	53,055
Machinery and equipment		77,918			74,122
Total cost		133,986			127,177
Accumulated depreciation		(68,522	)		(65,459	)
Property, plant and equipment, net	$	65,464		$	61,718

Summary of Depreciation Expense on Property, Plant and Equipment, Including Demo Units and Assets under Capital Leases

The following table summarizes depreciation expense on property, plant and equipment, including demo units and assets under capital leases (in thousands):

	Year Ended December 31,
	2018		2017		2016
Depreciation expense	$	11,442	$	9,838	$	8,558

Summary of Total Accumulated Depreciation on Assets under Capital Leases

The following table summarizes total accumulated depreciation on assets under capital leases as of the dates indicated (in thousands):

	December 31,
	2018		2017
Accumulated depreciation on assets under capital leases	$	6,901	$	6,097

Accrued Expenses and Other Current Liabilities

The following table summarizes accrued expenses and other current liabilities as of the dates indicated (in thousands):

	December 31,
	2018		2017
Accrued compensation and benefits	$	24,545	$	17,348
Accrued warranty		4,510		4,835
Contract liabilities, current portion		4,165		4,790
Other		13,075		16,341
Total	$	46,295	$	43,314

Accrued Warranty

The following table summarizes changes in accrued warranty for the periods indicated (in thousands):

	Year Ended December 31,
	2018			2017			2016
Balance at beginning of year	$	4,835		$	3,142		$	3,335
Provision charged to cost of revenue		3,111			3,169			1,673
Warranty liabilities acquired from acquisitions		—			1,307			23
Use of provision		(3,341	)		(2,857	)		(1,849	)
Foreign currency exchange rate changes		(95	)		74			(40	)
Balance at end of year	$	4,510		$	4,835		$	3,142